(1) Field of the Invention
This invention relates a substrate treating apparatus for treating substrates such as semiconductor wafers or glass substrates for liquid crystal displays (hereinafter called simply substrates) with treating liquids such as deionized water and chemicals. More particularly, the invention relates to a technique for performing drying treatment of substrates by supplying an inert gas such as nitrogen gas containing an organic solvent such as isopropyl alcohol.
(2) Description of the Related Art
A conventional substrate treating apparatus of this type includes a treating tank for storing treating liquids and receiving substrates for treatment, a chamber surrounding the treating tank, a lift mechanism for supporting the substrates and vertically movable between a process position inside the treating tank and a wait position above the treating tank and inside the chamber, and nozzles disposed in upper positions inside the chamber for supplying nitrogen gas containing isopropyl alcohol into the chamber (see Japanese Unexamined Patent Publication No. 2004-63513 (FIG. 1), for example).
The conventional apparatus with the above construction has the following drawbacks.
In the conventional apparatus, when the treating tank stores deionized water, the treating tank itself is at a low temperature, resulting in a drawback of the isopropyl alcohol contained in the inert gas condensing on the treating tank. Such condensation lowers the density of the isopropyl alcohol supplied into the chamber, so that the isopropyl alcohol cannot fully replace the deionized water adhering to the substrates, and thus a possibility of insufficient drying performance.
When not only the treating tank but the chamber itself lowers in temperature, the isopropyl alcohol may condense in the chamber, causing the same problem as above.